Power semiconductor components usually have a drift zone that takes up a reverse voltage when a rectifying junction of the component, e.g. a pn-junction or a Schottky junction, is in a blocking state. The drift zone has a thickness that is adapted to the desired voltage blocking capability of the power semiconductor component. That is, the higher the voltage blocking capability of the power semiconductor component the higher the thickness of the drift zone and the lower the doping of the same. In terms of low switching oscillations, a variation of the vertical doping profile of the drift zone is beneficial. In detail, a profile exhibiting a local maximum in a depth below the rectifying junction, followed by a continuous decrease of the doping concentration towards a field-stop layer is most desired.
However, economically producing a thick drift zone having a pre-defined doping profile is challenging. Implanting or diffusing of electrically active dopants into a thick semiconductor material is hardly practicable in view of the required implantation or diffusion depths. Epitaxially growing a thick drift zone is, on the one hand, time-consuming, and, on the other hand, controlling the epitaxial process in order to achieve dopant concentrations required for power semiconductor components having high blocking voltages is difficult. In case of an n-doped drift zone, radiation-induced donors may be used. After irradiating the wafer with high-energy particles, e.g. protons, and a subsequent thermal process, donors are generated following the damage concentration profile of the implantation. For a single implantation, this profile exhibits a continuous increase towards the bragg-peak of the implantation. Hence, conventional implantation techniques require Bragg peaks at different implantation depths which means implanting high-energy particles with significantly different implantation energies. This is leads to an undesired process with multiple subsequent steps, significantly increasing the process time and likelihood of errors.
Hence, there is a need for an improved method that can be used for the production of a power semiconductor component having a high blocking voltage, in particular for the production of a power semiconductor component having a doping concentration with a local maximum in the drift zone.